A bi-directional HPTLC development method for the detection of low levels of aflatoxin in maize extracts

A bi-directional high performance thin layer chromatography (HPTLC) method for the determination of low levels of aflatoxin in extracts of maize has been evaluated. The method, using diethylether and chloroform:xylene:acetone (6∶3∶1) as the two developing solvents was found to have a limit of detection of 0.8 (B1), 0.4 (B2), 1.7 (G1) and 0.4 (G2) μg/kg respectivety, with CVs equal or less than 1.7% (B1), 2.5% (B2), 3.1% (G1), and 3.1% (G2). Inter-plate variation was significantly greater than intra-plate variation. Compared with two-dimensional HPTLC methods, a 15 to 30 fold improvement in the sample capacity per plate is achieved and positioning errors are much reduced during densitometry

Evaluation of instrumentation used for high performance thin-layer chromatography of aflatoxins

Instrumentation used for high performance thin layer chromatography (HPTLC) of aflatoxins has been evaluated. Optimum sensitivity, accuracy and precision resulted when a combination of a fully automated TLC sampler, an unsaturated conventional TLC glass chamber and a monochromatic densitometer were employed. Benzene: acetonitrile (98: 2 v/v) was found to be the most suitable sample application solvent. These findings are being used to develop a rapid, simple and reproducible method for the analysis of aflatoxins